It allows programs to read and write logical records within physical blocks of data, as opposed to the less advanced Basic sequential access method ( BSAM ) which allows programs to access physical blocks of data, but provides no support for accessing logical records within blocks.
12.
It allows programs to read and write logical records within physical blocks of data, as opposed to the less advanced Basic sequential access method ( BSAM ) which allows programs to access physical blocks of data, but provides no support for accessing logical records within blocks.
13.
In the DD statement, the BLKSIZE is specified as a non-zero value and this, then, results in a program-specified LRECL ( logical record length ) and a JCL-specified BLKSIZE ( physical block size ), with the merge of the two becoming the permanent definition of the dataset.
14.
If the dataset is unblocked, that is, the logical record length ( LRECL ) is equal to the physical block size ( BLKSIZE ), BSAM may be utilized to simulate a directly accessed dataset using NOTE and POINT on any supported direct access device type ( DEVD = DA ), and some primitive applications were designed in this way.
15.
DLGs are available in two different formats : optional format, a simple-to-use format that incorporates an 80-byte logical record length, the UTM ground coordinate system, and topology linkages contained in line, node and area elements; and Spatial Data Transfer Standard ( SDTS ) format, a format that facilitates transferring of spatial data between different computer systems.
